This invention relates to an adjustable seat basket for providing lumbar support.
Adjustable seat baskets, located in a seat back, are used to provide controllably varying amounts of lumbar support to a person sitting in the seat. The primary components of existing adjustable seat baskets are a basket assembly, a hinge assembly and an adjustment mechanism.
The hinge assembly is attached to the seat back and a first end of the basket assembly. It fixes the basket assembly to the backrest while allowing the basket assembly to pivot relative to the seat back. The second end of the basket assembly bears on the seat back but is not fixed to the seat back, other than being generally held in place by the seat upholstery. Thus the second end of the basket assembly is free to both pivot relative to the seat back and to move up or down the seat back and relative to the first end of the basket assembly. The adjustment mechanism reversably draws the first and second ends of the basket together causing the basket assembly to curve and extend outward from the backrest to provide lumbar support.
Such adjustable seat baskets are complicated to manufacture and assemble. The basket frame and adjustment mechanism often comprise several parts. The hinge assembly comprises three additional parts; a hinge bracket (connected to the seat back), a hinge pin, and a lock plate (connected to the basket assembly). Further, the hinge requires lubrication and can wholly or partially seize and interfere with the smooth motion of the adjustable seat basket.
The present invention is directed at an improved adjustable seat basket that is simple and inexpensive to manufacture and avoids friction wearing surfaces.
In one aspect, the invention provides an adjustable seat basket mountable on a seat back comprising a unitary structure of resilient material having:
(a) a mounting tab;
(b) a living hinge adjacent the mounting tab; and,
(c) a basket having a proximal side adjacent the living hinge and a distal side relative to the living hinge.
The resilient material is spring steel preferably between 0.5 mm and 0.65 mm thick. The living hinge is preferably narrower than the basket and has a radius between 8 and 12 mm. The basket has at least one pivoting tab which is part of the unitary construction for attaching an adjustment mechanism near at least one of the proximal side of the basket and the distal side of the basket. The adjustable seat basket also has a curved surface which is part of the unitary construction adjacent to the distal side of the basket, the curved surface slidably engageable with the seat back.
The adjustable seat basket has an adjustment mechanism attached to it at a proximal point near the living hinge and at a distal point near the distal side of the basket and which is operable to releasably shorten the straight line distance between the proximal point and distal point. Preferably, the adjustment mechanism, when operated to allow the maximum straight line distance between the proximal point and distal point, exerts a residual tensile force on the adjustable seat basket between the proximal point and distal point such that the basket remains slightly curved.
In another aspect, the invention provides an adjustable seat basket mountable on a seat back comprising:
(a) a mounting tab;
(b) a hinge adjacent to the mounting tab;
(c) a first extending surface having a first end and a second end, the first end adjacent to the hinge and the second end extending away from the seat back;
(d) a basket surface having a first edge and a second edge, the first edge adjacent to the second end of the first extending surface; and,
(e) a second extending surface having a first side and a second side, the first side adjacent to the second edge of the basket surface and the second side extending towards the seat back
wherein the adjustable seat basket is a unitary construction of a resilient material and the hinge is a living hinge.
The resilient material is spring steel preferably between 0.5 mm and 0.65 mm thick. The living hinge is preferably narrower than the basket and has a radius between 8 and 12 mm. The basket surface has at least one pivoting tab which is part of the unitary construction for attaching an adjustment mechanism near at least one of the first edge and second edge. There is also a curved surface which is part of the unitary construction adjacent to the second side of the second extending surface, the curved surface slidably engageable with the seat back.
The adjustable seat basket has an adjustment mechanism attached to the adjustable seat basket at a proximal point near the living hinge and at a distal point near the second edge of the basket surface or the second extending surface which is operable to releasably shorten the straight line distance between the proximal point and distal point. Preferably, the adjustment mechanism, when operated to allow the maximum straight line distance between the proximal point and distal point, exerts a residual tensile force on the adjustable seat basket between the proximal point and distal point such that the basket surface remains slightly curved.
The adjustable seat basket has darts in the resilient material between the basket surface and the first extending surface and second extending surface. The basket surface and the living hinge are more easily bendable than the resilient material between the basket surface and the first extending surface and second extending surface.
The interior angles between the basket surface and the first extending surface and between the basket surface and the second extending surface are each between 90 degrees and 135 degrees. Preferably, the length and interior angle relative to the basket surface of the first extending surface and second extending surface are similar. The adjustable seat basket is generally trapezoidal, the basket surface being at the top of the trapezoid, when viewed from the side in a flat position.